This invention relates to spot-type disc brakes and more particularly to a sliding guide arrangement for floating-caliper spot-type disc brakes.
In floating-caliper spot-type disc brakes, there exists the problem of providing a movable guiding arrangement for the brake caliper at the fixed brake carrier, which, in order to achieve a high degree of efficiency, must have easy motion and be insusceptible to jamming even when subjected to loads, must not be impaired either by corrosion or by dirt, and must have no tendency to chatter and rattle under the impact of shocks and vibrations.
In a spot-type disc brake known from the U.S. Pat. No. 3,616,879, which has a brake caliper slidably guided in a central opening of a brake carrier which straddles the brake disc, the brake carrier is provided with V-shaped grooves aligned parallel to the axis of the brake disc for engagement with corresponding projections from the brake-caliper section straddling the brake disc. Thus, the guiding arrangement consists of two prisms aligned parallel to each other and therefore is statically undefined. In order to reduce the tendency of jamming employing this known guiding arrangement and to compensate for variations in manufacturing tolerances, leaf-spring elements are installed between the guiding element of the brake carrier and the guiding element of the brake caliper. The functioning capability of the guiding arrangement is therefore largely dependent on the durability of these spring elements. In addition to this, the springs are required to generate a relatively high biassing force to be able to absorb the forces of inertia occurring during shocks. A further disadvantage of this known design lies in the fact that the contact faces between the sliding portions are relatively large so that the guiding arrangement may jam more readily due to corrosion.